The recovery of hydrocarbons from subterranean zones relies on the process of drilling wellbores. This process includes drilling equipment situated at the surface and a drill string extending from the surface equipment to the formation or subterranean zone of interest. The drill string can extend thousands of feet or meters below the surface. The terminal end of the drill string includes a drill bit for drilling, or extending, the wellbore. The process also relies on some sort of drilling fluid system, in most cases a drilling “mud”. The mud is pumped through the inside of the drill string, which cools and lubricates the drill bit and then exits the drill bit and carries rock cuttings back to the surface. The mud also helps control bottom hole pressure and prevents hydrocarbon influx from the formation into the wellbore and potential blow out at the surface.
In some drilling operations, a “mud motor” may be provided. Mud motors are commonly used to drive drill bits in directional drilling. A mud motor uses the flow of drilling fluid to generate rotary motion. This rotary motion may be used for driving a drill bit, for example.
The downhole environment in which a mud motor is used may be harsh. The outside of a mud motor may be subjected to wear through abrasion by materials carried in the drilling fluid, cavitation of the drilling fluid, friction or impacts with the sides of the wellbore and the like. Excessive abrasion can damage the mud motor or other components in a drill string. In extreme cases enough material can be worn away that the mud motor or other drill string component can become weak and fail (e.g. twist off or disconnect).
There is a need for alternative structures useful for protecting mud motors and other drill string components for protecting mud motors and other drill string components from wear and for wear-resistant mud motors and other drill string components.